Phased array control circuit for controlling directivity of a beam-formed signal

ABSTRACT

Register banks are used to allow for fast beam switching in a phased array system. Each beam forming channel is associated with a register bank containing M register sets for configuring such things as gain/amplitude and phase parameters of the beam forming channel. The register banks for all beam forming channels can be pre-programmed and then fast beam switching circuitry allows all beam forming channels across the array to be switched to use the same register set from its corresponding register bank at substantially the same time, thereby allowing the phased array system to be quickly switched between various beam patterns and orientations. Active power control circuitry may be used to control the amount of electrical power provided to or consumed by one or more individual beam forming channels such as to reduce DC power consumption of the array and/or to selectively change the effective directivity of the array.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This patent application is a continuation of, and therefore claimspriority from, U.S. patent application Ser. No. 17/483,230 entitledPHASED ARRAY CONTROL CIRCUIT FOR CONTROLLING DIRECTIVITY OF ABEAM-FORMED SIGNAL filed Sep. 23, 2021, which is a continuation of, andtherefore claims priority from, U.S. patent application Ser. No.17/099,238 entitled PHASED ARRAY CONTROL CIRCUIT FOR CONTROLLING THEEFFECTIVE SHAPE OF A BEAM-FORMED SIGNAL filed Nov. 16, 2020 (U.S. Pat.No. 11,133,603 having issue date Sep. 28, 2021), which is a continuationof, and therefore claims priority from, U.S. patent application Ser. No.16/436,116 entitled PHASED ARRAY CONTROL CIRCUIT filed Jun. 10, 2019(U.S. Pat. No. 10,862,222 issued Dec. 8, 2020), which is a continuationof, and therefore claims priority from, U.S. patent application Ser. No.15/253,426 entitled PHASED ARRAY CONTROL CIRCUIT filed Aug. 31, 2016(U.S. Pat. No. 10,320,093 issued Jun. 11, 2019), each of which is herebyincorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention generally relates to phased arrays and, more particularly,the invention relates to a phased array control circuit.

BACKGROUND OF THE INVENTION

Active electronically steered antenna systems (“AESA systems,” a type of“phased array system”) form electronically steerable beams for a widevariety of radar and communications systems. To that end, AESA systemstypically have a plurality of beam forming elements (e.g., antennas)that transmit and/or receive energy so that the signal on each beamforming element can be coherently (i.e., in-phase and amplitude)combined (referred to herein as “beam forming” or “beam steering”).Specifically, many AESA systems implement beam steering by providing aunique RF phase shift and gain setting (phase and gain togetherconstitute a complex beam weight) between each beam forming element anda beamforming or summation point.

The number and type of beam forming elements in the phased array systemcan be selected or otherwise configured specifically for a givenapplication. A given application may have a specified minimumequivalent/effective isotropically radiated power (“EIRP”) fortransmitting signals. Additionally, or alternatively, a givenapplication may have a specified minimum G/T (analogous to asignal-to-noise ratio) for receiving signals, where:

-   -   G denotes the gain or directivity of an antenna, and    -   T denotes the total noise temperature of the receive system        including receiver noise figure, sky temperature, and feed loss        between the antenna and input low noise amplifier.

SUMMARY OF VARIOUS EMBODIMENTS

In accordance with one embodiment of the invention, a phased arraysystem comprises a plurality of beam forming elements; a plurality ofbeam forming channels, each beam forming channel including beam formingcircuitry configured to process signals for a discrete beam formingelement; and for each beam forming channel, a corresponding registerbank comprising a plurality of addressable and programmable registersets and fast beam switching circuitry that receives fast beam switchingcontrol signals from a fast beam switching control interface, eachregister set configured to store operating parameters for the beamforming channel, the fast beam switching circuitry configured to provideoperating parameters from a selected one of the register sets to thebeam forming channel based on the fast beam switching control signalsfrom the fast beam switching control interface.

In accordance with another embodiment of the invention, a beam formingintegrated circuit for use in a phased array system comprises at leastone beam forming channel, each beam forming channel including beamforming circuitry configured to process signals for a discrete beamforming element; and for each beam forming channel, a correspondingregister bank comprising a plurality of addressable and programmableregister sets and fast beam switching circuitry that receives fast beamswitching control signals from a fast beam switching control interface,each register set configured to store operating parameters for the beamforming channel, the fast beam switching circuitry configured to provideoperating parameters from a selected one of the register sets to thebeam forming channel based on the fast beam switching signals from thefast beam switching control interface.

In various alternative embodiments, the fast beam switching circuitrymay be configured to allow for random access to the register sets,sequential access to the register sets, and/or round-robin access to theregister sets. A programming interface may be included for programmingthe register banks. The fast beam switching control interface may bepart of the programming interface or may be separate from theprogramming interface. The fast beam switching circuitry may beconfigured to select the register set based on a parallel address orbased on a clock signal. The operating parameters may include anamplitude parameter and a phase parameter. At least one of the beamforming channels may be a dual-mode beam forming channel includingtransmit path circuitry for operating in a transmit mode, receive pathcircuitry for operating in a receive mode, and mode selection circuitryfor switching between the transmit mode and the receive mode based on amode selection parameter in the operating parameters for the beamforming channel. At least one beam forming channel may include activepower control circuitry configured to selectively control DC powerconsumption of the beam forming channel based on a power controlparameter for the beam forming channel for at least one of (1) reducingDC power consumption of the phased array system or (2) selectivelychanging the effective directivity of the phased array system. The powercontrol parameter for the beam forming channel may be derived from theoperating parameters provided to the beam forming channel and/or from aregister separate from the register bank. The active power controlcircuitry may be configured to selectively turn on and off at least somebeam forming circuitry of the beam forming channel and/or to selectivelyadjust a power level of at least some beam forming circuitry of the beamforming channel. A phased array system may include a plurality of beamforming integrated circuits, each beam forming integrated circuitimplementing at least one beam forming channel and correspondingregister bank. The register banks may include a sufficient number ofregister sets for being preprogrammed with parameters for beams coveringa full 2D scan volume of the phased array system.

In accordance with another embodiment of the invention, a phased arraysystem comprises a plurality of beam forming elements and a plurality ofbeam forming channels, each beam forming channel including beam formingcircuitry configured to process signals for a discrete beam formingelement, wherein at least one beam forming channel further includesactive power control circuitry configured to selectively control DCpower consumption of the beam forming channel based on a power controlparameter for the beam forming channel for at least one of (1) reducingDC power consumption of the phased array system or (2) selectivelychanging the effective directivity of the phased array system.

In accordance with another embodiment of the invention, a beam formingintegrated circuit for use in a phased array system comprises at leastone beam forming channel, each beam forming channel including beamforming circuitry configured to process signals for a discrete beamforming element, wherein at least one beam forming channel furtherincludes active power control circuitry configured to selectivelycontrol DC power consumption of the beam forming channel based on apower control parameter for the beam forming channel for at least one of(1) reducing DC power consumption of the phased array system or (2)selectively changing the effective directivity of the phased arraysystem.

In various alternative embodiments, each beam forming channel mayinclude at least one register set for providing operating parameters tothe beam forming channel, in which case the power control parameter forthe beam forming channel may be derived from such operating parametersor may be provided via at least one power control register separate fromsuch register sets. The active power control circuitry may be configuredto selectively turn on and off at least some beam forming circuitry ofthe beam forming channel and/or to selectively adjust a power level ofat least some beam forming circuitry of the beam forming channel.

In accordance with another embodiment, a beam forming method comprisespreconfiguring a plurality of register sets in each of a plurality ofregister banks with parameters for beams covering a full 2D scan volumeof a phased array system; selecting a register set for a beam formingoperation; and sending fast beam switching control signals to activatethe selected register set across the plurality of register banks forperforming the beam forming operation.

Additional embodiments may be disclosed and claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Those skilled in the art should more fully appreciate advantages ofvarious embodiments of the invention from the following “Description ofIllustrative Embodiments,” discussed with reference to the drawingssummarized immediately below.

FIG. 1 schematically shows one exemplary application of a phased arraysystem that may be configured in accordance with illustrativeembodiments of the invention.

FIG. 2 is a schematic block diagram of the phased array system of FIG. 1, in accordance with certain exemplary embodiments.

FIG. 3 is a schematic block diagram of a portion of a phased arraysystem configured in accordance with certain illustrative embodiments.

FIG. 4 is a block diagram schematically showing components of a beamforming ASIC, in accordance with certain exemplary embodiments known inthe art.

FIG. 5 is a block diagram schematically showing components of a beamforming channel at a high level, in accordance with certain exemplaryembodiments.

FIG. 6 schematically shows an exemplary architecture of the amplitudeand phase control circuitry of a beam forming channel including a singlevector modulation circuit, in accordance with certain exemplaryembodiments.

FIG. 7 schematically shows an exemplary architecture of the amplitudeand phase control circuitry of a beam forming channel including separategain/amplitude and phase control circuits, in accordance with certainexemplary embodiments.

FIG. 8 is a block diagram schematically showing components of theamplitude and phase control circuitry for use with dual-mode elements,in accordance with certain exemplary embodiments.

FIG. 9 shows an exemplary write sequence and write sequence timingrequirements, in accordance with certain exemplary embodiments.

FIG. 10 is a block diagram schematically showing components of a beamforming ASIC having register banks, in accordance with certain exemplaryembodiments.

FIG. 11 is a block diagram schematically showing components of aregister bank, in accordance with certain exemplary embodiments.

FIG. 12 is a block diagram schematically showing components of a beamforming channel including active power control in accordance withcertain embodiments.

FIG. 13 schematically shows the contents of a beam forming controlcodeword for controlling a beam forming channel, in accordance withcertain embodiments.

FIG. 14 schematically shows the use of a separate power control registeras part of each register set, in accordance with certain exemplaryembodiments.

FIG. 15 schematically shows the use of a separate power control registerseparate from the register sets, in accordance with certain embodiments.

FIG. 16 schematically shows a fast beam switching controller foraddressing through M discrete control lines, in accordance with certainexemplary embodiments.

FIG. 17 schematically shows a fast beam switching controller foraddressing through a counter, in accordance with certain exemplaryembodiments.

FIG. 18 schematically shows a fast beam switching controller foraddressing through a separate fast beam switching clock/data line, inaccordance with certain exemplary embodiments.

FIG. 19 schematically shows a fast beam switching controller foraddressing through a separate SPI-based interface, in accordance withcertain exemplary embodiments.

FIG. 20 schematically shows a fast beam switching controller foraddressing through a clock signal, in accordance with certain exemplaryembodiments.

FIG. 21 schematically shows an alternate fast beam switching controllerfor addressing through a clock signal, in accordance with certainexemplary embodiments.

FIG. 22 schematically shows a scan volume filled by N beams, inaccordance with certain exemplary embodiments.

FIG. 23 schematically shows an example for selectively reprogrammingregister sets for dynamically framing a beam forming target, inaccordance with certain exemplary embodiments.

FIG. 24 schematically shows exemplary register set configurations forthe example of FIG. 23 , in accordance with certain embodiments.

FIG. 25 is a flowchart for fast beam switching, in accordance withcertain exemplary embodiments.

FIG. 26 is a flowchart for fast beam switching in the context ofpreconfiguring parameters covering a full 2D scan volume, in accordancewith certain exemplary embodiments.

FIG. 27 is a flowchart for fast beam switching in the context of framinga target area, in accordance with certain exemplary embodiments.

FIG. 28 is a flowchart for selectively activating and deactivating beamforming channels such as for reducing DC power consumption or toselectively change the effective directivity of the array, in accordancewith certain exemplary embodiments.

It should be noted that the foregoing figures and the elements depictedtherein are not necessarily drawn to consistent scale or to any scale.Unless the context otherwise suggests, like elements are indicated bylike numerals.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Definitions. As used in this description and the accompanying claims,the following terms shall have the meanings indicated, unless thecontext otherwise requires:

A “set” includes one or more members.

A “beam forming element” (sometimes referred to simply as an “element”)is an element that is used to transmit and/or receive a signal for beamforming. Different types of beam forming elements can be used fordifferent beam forming applications. For example, the beam formingelements may be RF antennas for RF applications (e.g., radar, wirelesscommunication system such as 5G applications, satellite communications,etc.), ultrasonic transducers for ultrasound applications, opticaltransducers for optical applications, microphones and/or speakers foraudio applications, etc. Typically, the signal provided to or from eachbeam forming element is independently adjustable, e.g., as togain/amplitude and phase.

A “beam-formed signal” is a signal produced by or from a plurality ofbeam forming elements. In the context of the present invention, there isno requirement that a beam-formed signal have any particularcharacteristics such as directionality or coherency.

A “phased array system” is a system that includes a plurality of beamforming elements and related control logic for producing and adaptingbeam-formed signals.

For convenience, the term “beam forming” is sometimes abbreviated hereinas “BF.”

In certain exemplary embodiments, register banks are used to allow forfast beam switching (FBS) in a phased array system. Specifically, eachbeam forming channel is associated with a register bank containing Mregister sets for configuring such things as gain/amplitude and phaseparameters of the beam forming channel. The register banks for all beamforming channels can be pre-programmed and then fast beam switchingcircuitry allows all beam forming channels across the array to beswitched to use the same register set from its corresponding registerbank at substantially the same time, thereby allowing the phased arraysystem to be quickly switched between various beam patterns andorientations. Additionally or alternatively, active power controlcircuitry may be used to control the amount of electrical power providedto or consumed by one or more individual beam forming channels (e.g.,powering off circuitry in unneeded beam forming channels or reducingpower to certain beam forming channels) such as to reduce DC powerconsumption of the array and/or to selectively change the effectivedirectivity of the array. In some embodiments, fast beam switching andactive power control may be used together, e.g., with power controlparameters set through the fast beam switching circuitry or by separatecircuitry.

FIG. 1 schematically shows two exemplary applications of phased arraysystems 100 that may be configured in accordance with illustrativeembodiments of the invention. In these examples, the phased arraysystems 100 implement AESA systems (also identified by reference number“100”), which, as known by those skilled in the art, form a plurality ofelectronically steerable beams that can be used for a wide variety ofapplications. For example, the application in FIG. 1(A) is implementedas a radar system in which a beam-formed signal may be directed towardan aircraft or other object in the sky (e.g., to detect or trackposition of the object), while the application in FIG. 1(B) isimplemented as a wireless communication system (e.g., 5G) in which abeam-formed signal may be directed toward a particular user (e.g., toincrease the effective transmit range of the AESA system or to allow forgreater frequency reuse across adjacent or nearby cells. Of course,those skilled in the art use AESA systems 100 and other phased arraysystems 100 in a wide variety of other applications, such as RFcommunication, optics, sonar, ultrasound, etc. Accordingly, discussionof radar and wireless communication systems are not intended to limitall embodiments of the invention.

FIG. 2 is a schematic block diagram of the phased array system 100 ofFIG. 1 , in accordance with certain exemplary embodiments. Among otherthings, the phased array system 100 includes a beam forming controller202, a signal distribution system 204, and a number of beam formingintegrated circuits (ASICs) 206, each of which supports a number of beamforming elements 208 (e.g., RF antennas for operation in the exemplaryradar or 5G system). The phased array system 100 includes X beam formingASICS 206, with each beam forming ASIC 206 supporting Y beam formingelements. Thus, the phased array system 100 includes (X*Y) beam formingelements.

The phased array system 100 of FIG. 2 can be used for transmitting abeam-formed signal via the beam forming elements 208 and/or to produce abeam-formed signal via the beam forming elements 208. Thus, the signaldistribution system 204 may be configured to distribute the beam formingsignal to each of the beam forming ASICs 206 and/or to produce acombined beam-formed signal from signals received from the beam formingASICs 206.

FIG. 3 is a schematic block diagram of a portion 300 of a phased arraysystem 100 configured in accordance with certain illustrativeembodiments. Specifically, the portion 300 is implemented as a laminarphased array having a printed circuit board 302 (i.e., a base orsubstrate) supporting a plurality of beam forming ASICs 206 (representedby the solid black boxes), beam forming elements 208 (represented by thehatched boxes, e.g., RF antennas), and interconnection logic forcoupling the beam forming ASICs 206 to the common beam forming signalline(s) and the common control (CTRL) line(s).

In this example, the beam forming elements 208 are formed as a pluralityof patch antennas on the laminar printed circuit board 302, although itshould be noted that the present invention is not limited to patchantennas or to a laminar printed circuit board. In this example, eachbeam forming ASIC 206 supports two beam forming elements (e.g.,antennas), although in various alternative embodiments, each beamforming ASIC 206 may support one, two, or more beam forming elements(e.g., four beam forming elements per beam forming ASIC). Although onlya small number of beam forming ASICs 206 and beam forming elements 208are shown in the portion 300 of FIG. 3 , it should be noted that variousalternative embodiments may be configured such that the portion 300includes a smaller number of beam forming ASICs 206 and/or beam formingelements 208 or may be configured such that the portion 300 includes alarger number of beam forming ASICs 206 and/or beam forming elements 208(e.g., hundreds or even thousands, of beam forming elements 208). Itshould be noted that alternative embodiments may be implemented withjust the beam forming elements 208 on the printed circuit board 302. Italso should be noted that alternative embodiments may be implementedwith the beam forming controller 202 and/or the RF power distribution204 system on the printed circuit board 302.

The phased array system 100 can have any of a variety of different typesof beam forming elements 208. For example, the phased array system 100can have one or more transmit-only elements, one or more receive-onlyelements, and/or one or more dual-mode elements that are capable of bothtransmitting and receiving signals. For convenience, a beam formingchannel that supports a dual-mode beam forming elements may be referredto herein as a “dual-mode beam forming channel” (sometimes also referredto as a “beam forming transceiver channel”). Embodiments typicallyinclude all the same type of beam forming element, i.e., either alltransmit-only elements, all receive-only elements, or all dual-modeelements, and, furthermore, embodiments that include dual-mode elementstypically operate all of the dual-mode elements in the same mode at anygiven time (e.g., transmit during one phase of operation, receive duringanother phase of operation, e.g., alternating between transmit andreceive modes). However, embodiments may include both transmit-onlyelements and receive-only elements, in which case it is typical for thetransmit-only elements to be operated during one phase of operation andfor the receive-only elements to be operated during another phase ofoperation (e.g., alternating between transmit and receive modes). Insome embodiments, transmit and receive modes can operate simultaneously,e.g., having both transmit-only and receive-only elements operating atthe same time, or simultaneously having some dual-mode elementsconfigured to transmit and some dual-mode elements configured toreceive. The beam forming controller 202 controls the mode and operationof the beam forming ASICs 206 and beam forming elements 208.

As discussed above, each beam forming ASIC 206 supports one or more ofthe beam forming elements 208. In illustrative embodiments, each beamforming ASIC 206 is configured with at least the minimum number offunctions to accomplish the desired effect. Indeed, beam forming ASICsfor use with dual-mode elements typically have some differentfunctionality than that of beam forming ASICs for use with transmit-onlyor receive-only elements. For example, beam forming ASICs for use withdual-mode elements typically include switching circuitry for switchingeach dual-mode element between a transmitter and a receiver.Accordingly, beam forming ASICs for use with transmit-only orreceive-only elements typically have a smaller footprint than beamforming ASICs for use with dual-mode elements.

As an example, depending on its role in the configuration of the phasedarray system 100, each beam forming ASICs 206 may include some or all ofthe following functions:

phase shifting,

amplitude controlling/signal weighting,

switching between transmit mode and receive mode,

output amplification to amplify output signals to the beam formingelement(s),

input amplification to amplify input signals from the beam formingelement(s), and

power combining and splitting between beam forming elements.

Indeed, some embodiments of the beam forming ASICs 206 may haveadditional or different functionality, although illustrative embodimentsare expected to operate satisfactorily with the above noted functions.Those skilled in the art can configure the beam forming ASICs 206 in anyof a wide variety of manners to perform those functions. For example,output amplification may be performed by a power amplifier, inputamplification may be performed by a low noise amplifier, phase shiftingmay use conventional phase shifters, and switching functionality may beimplemented using conventional transistor-based switches.

Each beam forming ASIC 206 preferably operates on at least one beamforming element 208 in the array. In certain exemplary embodiments, onebeam forming ASIC 206 can operate on multiple beam forming elements 208,e.g., two or four beam forming elements 208. Of course, those skilled inthe art can adjust the number of beam forming elements 208 sharing abeam forming ASIC 206 based upon the application. Among other things,sharing the beam forming ASICs 206 between multiple beam formingelements 208 in this manner generally reduces the required total numberof beam forming ASICs 206, which in some cases may reduce the requiredsize of the printed circuit board 302 (or in some cases allow a greaternumber of beam forming elements to be placed on the printed circuitboard 302), reduce the power consumption of the phased array system 100,and reduce the overall cost of the phased array system 100.

FIG. 4 is a block diagram schematically showing components of a beamforming ASIC 206, in accordance with certain exemplary embodiments knownin the art. Among other things, the beam forming ASIC 206 includes aSerial Peripheral Interface (SPI) controller 402 or other appropriatecontroller for interfacing with the beam forming controller 202 via thecontrol (CTRL) signals, a signal distribution system 404 fordistributing the common beam forming signal to and/or from each of Ybeam forming channels 4081-408Y, and a register set 406 ₁-406 _(Y) forconfiguring each of the Y beam forming channels 408 ₁-408 _(Y),respectively. Each register set 406 may include one or more registersfor programming the complex beam weight of corresponding beam formingchannel 408. For example, each register set 406 may include a singleregister that is used to store a codeword including both gain/amplitudeand phase parameters for the corresponding beam forming channel 408, oreach register set 406 may include separate registers that are used tostore separate gain/amplitude and phase parameters for the correspondingbeam forming channel 408.

FIG. 5 is a block diagram schematically showing components of a beamforming channel 408 at a high level, in accordance with certainexemplary embodiments. Among other things, the beam forming channel 408includes amplitude and phase control circuitry 502 that adjusts thegain/amplitude and phase of the signal to or from the beam formingelement 208 based on gain/amplitude and phase parameters from thecorresponding register set 406. As discussed above, a beam formingchannel 408 may be configured as transmit-only, receive-only, ordual-mode, and phased array systems may be configured with alltransmit-only channels, all receive-only channels, all dual-modechannels, or a mix of different types of channels. A transmit-only ordual-mode beam forming channel typically includes transmit pathcircuitry including a power amplifier, while a receive-only or dual-modebeam forming channel typically includes receive path circuitry includinga low noise amplifier. The beam forming channel also may includeadditional amplifiers and/or buffers (e.g., for adding delay to a signalfor phase shifting).

FIGS. 6 and 7 schematically show two exemplary architectures of theamplitude and phase control circuitry 502, in accordance with certainexemplary embodiments. In FIG. 6 , the amplitude and phase controlcircuitry 502 includes a vector modulator circuit 601 that adjusts boththe amplitude and phase of the signal to or from the beam formingchannel 408 based on the gain/amplitude and phase parameters from thecorresponding register set 406. In FIG. 7 , the amplitude and phasecontrol circuitry 502 includes separate phase control circuitry 602 andamplitude control circuitry 604, where the phase control circuitry 602adjusts the phase of the signal to or from the beam forming channel 408based on phase parameters from the corresponding register set 406, andthe amplitude control circuitry 604 adjusts the gain/amplitude of thesignal to or from the beam forming channel 408 based on gain/amplitudeparameters from the corresponding register set 406. As mentioned above,the register set 406 may include a single register that is used to storea codeword including both gain/amplitude and phase parameters for thecorresponding beam forming channel 408, in which case the codeword maybe decoded to provide phase parameters to the phase control circuitry602 and gain/amplitude parameters to the amplitude control circuitry604, or the register set 406 may include separate registers that areused to store separate gain/amplitude and phase parameters for thecorresponding beam forming channel 408, in which case the phaseparameters from the phase register may be provided to the phase controlcircuitry 602 and the gain/amplitude parameters from the gain/amplituderegister may be provided to the amplitude control circuitry 604.

FIG. 8 is a block diagram schematically showing components of theamplitude and phase control circuitry 502 for use with dual-modeelements, in accordance with certain exemplary embodiments. Among otherthings, the amplitude and phase control circuitry 502 includes transmitpath circuitry 806, receive path circuitry 804, and switches 802 and808. The transmit path circuitry 806 may be configured substantially asdiscussed above with reference to FIGS. 6 and 7 for adjustinggain/amplitude and phase of signals being sent to the beam formingelement 208 from the signal distribution system 404, while the receivepath circuitry 804 may be configured substantially in the reverse of thetransmit path circuitry 806 for adjusting gain/amplitude and phase ofsignals received from the beam forming element 208 and provided to thesignal distribution system 404. The transmit path 806 and the receivepath 804 may be separate circuits, or, in some embodiments, may includesome common circuitry (e.g., the amplitude control circuitry and/or thephase control circuitry may be shared by the two signal paths). In thisexample, the register set 406 includes, in addition to gain/amplitudeparameters and phase parameters, a mode selection parameter to selectthe mode for the beam forming channel (e.g., transmit mode vs. receivemode). This mode selection parameter is used to control the switches 802and 808 to select the appropriate signal path, i.e., the transmit path806 for transmit mode and the receive path 804 for receive mode. Thegain/amplitude and phase parameters from the register set 406 areprovided to the appropriate signal path. The register set 406 mayinclude a single register that is used to store a codeword includinggain/amplitude parameters and phase parameters as well as the modeselection parameter for the corresponding beam forming channel 408, inwhich case the codeword may be decoded to provide the mode selectionparameter to the switches 802 and 808 and to provide phase parameters tophase control circuitry and gain/amplitude parameters to amplitudecontrol circuitry, or the register set 406 may include a separate modeselection register for the mode selection parameter, in which case themode selection parameter from the mode selection register may beprovided to the switches 802 and 808. It should be noted that, incertain alternative embodiments, the switches 802 and 808 may be omittedand instead the mode selection parameter used to enable the appropriatesignal path (e.g., power on the selected signal path circuitry and poweroff the other signal path circuitry).

In any case, transmit path circuitry in a transmit-only or dual-modebeam forming channel 408 typically includes a power amplifier, whilereceive path circuitry in a receive-only or dual-mode beam formingchannel 408 typically includes a low noise amplifier. The beam formingchannel 408 also may include additional amplifiers and/or buffers (e.g.,for adding delay to a signal for phase shifting).

In operation, the beam forming controller 202 configures each registerset 406 with beam forming parameters for the corresponding beam formingchannel 408, such as, for example, phase and gain parameters for thebeam forming channel, and, when the beam forming elements 208 aredual-mode elements, optionally also the mode for the beam formingchannel (e.g., transmit mode vs. receive mode).

From time to time, the beam forming controller 202 may need toreconfigure the operation of the phased array system 100, e.g., byswitching between transmit mode and receive mode and/or reconfiguringthe phase and gain parameters for each of the beam forming elements 208such as to change the effective shape, directivity, direction, or powerof a beam-formed signal. Effectively, the rate of such reconfigurationof the phased array system 100 is limited by the rate at which the beamforming controller 202 can write new parameters to Y registers in the Xbeam forming ASICs 206. In certain implementations, such reconfigurationmay involve at least (X*Y) write operations (e.g., one write operationper beam forming channel).

In the exemplary embodiment described above with reference to FIG. 4 ,each beam forming ASIC 206 includes an SPI controller 402 forinterfacing with the beam forming controller 202 (which also includes anSPI controller) over an SPI bus. Generally speaking, the beam formingcontroller 202 operates as the SPI bus master device and the beamforming ASICs 206 operate as SPI bus slave devices.

FIG. 9(A) shows an example of this write sequence, where an N-Bit wordis supplied by the beam forming controller 202 via the SPI Bus. TheN-bit word may include address information (e.g., to select the registerset that is being written) as well as the gain/amplitude and phaseparameters (e.g., in the form of a codeword) and possibly additionalinformation (e.g., a mode selection parameter for switching dual-modeelements between transmit mode and receive mode). At the end of theN-Bit sequence, the contents of the register set are overwritten and thecomplex beam weight of the beam forming channel is changed based on thecontents of the register set.

FIG. 9(B) shows typical timing requirements for writing multiple N-Bitwords by the beam forming controller 202 via the SPI Bus. As this figureshows, the time required to change the complex beam weight of a beamforming channel from Weight1 to Weight2 is Δt, where Δt is the sum ofthe timing overhead (required between writes) and the time required towrite the N-bit codeword. Thus, Δt is essentially a lower bound on thetime to reconfigure the entire array (e.g., if all register sets can bewritten concurrently across all beam forming ASICs), although the entirewrite sequence could take on the order of (X*Y*Δt) if each register setneeds to be written independently/sequentially or on the order of(X*Y*Δt)/P if P beam forming ASICs can be written in parallel, which isa bottleneck for the update time of the system.

Furthermore, if each beam forming channel 408 is reprogrammed uponcompletion of the write to the corresponding register set 406, then thebeam forming channels 408 (or various subsets of the beam formingchannels 408) could switch to the new configuration at slightlydifferent times, which could degrade the quality of beam formingoperations. This can be remedied, for example, by latching the currentcodewords being used by the beam forming channels while new codewordsare written and then activating all of the new codewords at the sametime using a common signal from the beam forming controller 202,although such a mechanism would not change the update time of thesystem, which still involves writing (X*Y) register sets.

Therefore, in certain embodiments, rather than each beam forming ASIC206 including a single register set for each beam forming channel, eachbeam forming ASIC includes a register bank for each beam formingchannel, where the register bank includes a plurality of register sets.The register banks can be pre-programmed with beam forming parametersfor multiple potential beam forming operations and then, using switchinglogic, individual register sets can be sent (via instructions from thebeam forming controller 202) simultaneously to their corresponding beamforming channels to effectuate particular beam forming operations. Theswitching logic can be configured for random access to the register setsof the register banks or for sequential or round-robin access to theregister sets of the register banks, typically asynchronously withrespect to the SPI interface 402. The complex beam weight of a givenbeam forming channel is determined by the parameters presented to thebeam forming channel from such switching.

FIG. 10 is a block diagram schematically showing components of a beamforming ASIC 206, in accordance with certain exemplary embodiments.Among other things, the beam forming ASIC 206 includes the SerialPeripheral Interface (SPI) controller 402 or other appropriatecontroller for interfacing with the beam forming controller 202 via thecontrol (CTRL) signals, the signal distribution system 404 fordistributing the common beam forming signal to and/or from each of the Ybeam forming channels 408 ₁-408 _(Y), and a register bank 1006 ₁-1006_(Y) for configuring the Y beam forming channels 408 ₁-408 _(Y),respectively. Each register bank includes M register sets 406 (forconvenience, referred to herein as register set 1 through register setM), where each register set 406 may include one or more registers forprogramming the complex beam weight (and optionally other parameters,e.g., the operating mode) of corresponding beam forming channel 408. Forexample, each register set 406 may include a single register that isused to store a codeword including both gain/amplitude and phaseparameters for the corresponding beam forming channel 408, or eachregister set 406 may include separate registers that are used to storeseparate gain/amplitude and phase parameters for the corresponding beamforming channel 408. A Fast Beam Switching (FBS) Controller 1002 outputsregister selection signals 1004 based on FBS signals 1003 received fromthe beam forming controller 202. For random access to the register setsin the register banks, the FBS signals 1003 may include addressesconveyed via a serial bus or a parallel bus (e.g., a four-bit parallelbus could be used to address 16 register sets) and the FBS Controller1002 may include an address decoder. For sequential or round-robinaccess to the register sets in the register bank, the FBS signals 1003may involve simple clock-like pulses and the FBS Controller 1002 mayinclude an address generator to step through the register sets at eachclock pulse. Other types of register selection configurations may beused in various alternative embodiments, and in some embodiments, theFBS Controller 1002 may be omitted, with FBS signals 1003 provideddirectly to and processed by the register banks 1006.

The FBS Controller 1002 and/or the corresponding FBS signals 1002 can beimplemented in any of a variety of ways, and the present invention isnot limited to any particular register selection technique. Withoutlimitation, the following are some exemplary register selectiontechniques:

1) Addressing Through M Discrete Control Lines

In this implementation, the FBS signals 1003 are P discrete linesprovided to the beam forming ASICs 206. These P discrete lines could beprocessed by the FBS Controller 1002 to generate register selectionsignals 1004 or could be fed directly to the register banks 1006(circumventing the need for a separate FBS Controller 1002) in whichcase the FBS signals 1003 could serve as the register selection signals1004. These P discrete lines can generate 2^(P) discrete addresses,thereby allowing the system to address up to 2^(P) register sets (e.g.,the number of register sets per register bank referred to as “M” in FIG.11 could equal 2^(P)).

FIG. 16 schematically shows an FBS Controller 1002 for addressingthrough M discrete control lines, in accordance with certain exemplaryembodiments. In this example, the FBS Controller 1002 includes a decoder1602 that is configured to decode the M discrete control lines of theFBS interface 1003 to produce the register selection signals 1004 (e.g.,decoded addresses). Alternatively, if no decoding is needed, block 1602may consist of a set of buffers/line drivers.

2) Addressing Through a Counter

In this implementation, the FBS signals 1003 can be as few as one line.This line can be toggled up and down by the host system, to update theaddress. The FBS Controller 1002 could count the number of times theline was toggled and from that count determine the selected register setand output the appropriate register selection signals 1004. The depth ofthe counter would determine the number of unique addresses that could begenerated and thus the number of register sets that could be supportedin the register banks. Additional control lines could be included inthis implementation to improve robustness. One example would be an“enable” line that gates the clock and resets the counter betweenaddress updates. Among other things, this could improve noise immunityand ensure that the state of each counter is consistent across multiplebeam forming ASICs 206 on the phased array system 100.

FIG. 17 schematically shows an FBS Controller 1002 for addressingthrough a counter, in accordance with certain exemplary embodiments. Inthis example, the FBS Controller 1002 includes a decoder 1702 and acounter 1704, and the FBS signals 1003 include two lines, namely a clockline (FBS_CLK) and an enable line (FBS_EN). The FBS_EN line “gates” theFBS_CLK signal so that only when the enable signal is active will thecounter start to accumulate, e.g., when the enable line is active, thedecoder 1702 passes the clock signal through to the counter 1704, andwhen the enable line is inactive, the value of the counter 1704 can bepassed as register selection signals 1004 to select the appropriateregister set. The enable signal can also be used to generate a resetpulse to reset the counter, e.g., the decoder 1702 monitors the enableline to detect a reset signal and generates a corresponding reset signalto the counter 1704 upon detecting the reset signal from the enableline. Among other things, gating the clock signal helps to provide noiseimmunity, and resetting the counter helps to guarantee that all of theFBS controllers are generating the same address.

3) Addressing Through a Separate Fast Beam Switching Clock/Data Line

In this implementation, the FBS signals 1003 may consist of a clock/dataline that works independently of the SPI Bus. In this approach, data isclocked in to the FBS Controller 1002 and stored to produce an addressfor selecting the register set.

FIG. 18 schematically shows an FBS Controller 1002 for addressingthrough a separate fast beam switching clock/data line, in accordancewith certain exemplary embodiments. In this example, the FBS Controller1002 includes a shift register 1802, and the FBS signals 1003 includetwo lines, namely a clock line (FBS_CLK) and a data line (FBS_DATA). TheFBS_DATA line carries the address data to be decoded and sent to theregister bank switches via register selection signals 1004. Data bitsare clocked in using the FBS_CLK line. The depth of the shift registerdictates the length of the address. One advantage to this approach isthat, for example, 32 (2{circumflex over ( )}6) states requires only 6clock cycles to update the address, whereas the counter of FIG. 17 mayrequire up to 31 clock pulses to update a state (e.g., if FBS address 31is desired).

4) Addressing Through a Separate SPI-Based Interface

In this implementation, the FBS signals 1003 could include a set oflines selected from the SPI Bus and/or a set of lines specifically forFBS control. The FBS Controller 1002 would operate as a secondary FBSSerial Peripheral Interface (FBS SPI) that deciphers clock/data signalsto generate an address for selecting the register set. FBS SPI writetimes would be much shorter than writing to the standard SPI, whichwould increase the beam switching rate.

FIG. 19 schematically shows an FBS Controller 1002 for addressingthrough a separate SPI-based interface, in accordance with certainexemplary embodiments. In this example, the FBS Controller 1002 includesa FBS Serial Peripheral Interface 1902 that shares data and clock lineswith the standard Serial Peripheral Interface 402. Here, the StandardSPI 402 generally would be designed to ignore communications that areintended for the FBS SPI 1902, while the FBS SPI 1902 generally would bedesigned to ignore communications that are intended for the standard SPI402. This can be accomplished, for example, through addressing,encoding, time-division multiplexing, frequency-division multiplexing,or other mechanism. As mentioned above, the FBS signals 1003 couldinclude a set of lines specifically for FBS control. For example, anadditional FBS enable line may be used to enable or disable the FBS SPI1902. This would allow for time division multiplexing between thestandard SPI 402 and the FBS SPI 1902.

5) Addressing Through a Clock Signal

In this implementation, the FBS signals 1003 could be a single line,where the beam forming controller 202 generates a clock pulse each timeit wants to move to the next successive register set in the registerbank. Based on such a clock signal, the FBS Controller 1002 couldgenerate the appropriate address selection signals 1004, or in someembodiments the FBS Controller 1002 could be omitted and instead theclock signal could be applied directly to the register bank wherecircuitry outputs the next successive register set at each clock pulse.This type of register selection mechanism could be used to providesequential access to the register sets (e.g., stepping from register set1 to register set M) or to provide round-robin access to the registersets (e.g., stepping from register set 1 to register set M and recyclingto register set 1). A “synchronization” signal could be sent by the beamforming controller 202 from time to time in order to reset or otherwisesynchronize all of the beam forming ASICs 206 (e.g., reset to the firstregister set).

FIG. 20 schematically shows an FBS Controller 1002 for addressingthrough a clock signal, in accordance with certain exemplaryembodiments. In this example, the FBS Controller 1002 includes a counter2002 that is incremented on each cycle of a clock signal (FBS_CLK),e.g., on the rising or falling edge, to produce register selectionsignals 1004 that step through the register sets and optionally recycleback to the first register set for round-robin addressing. A resetmechanism similar to that shown in FIG. 17 can be included to reset thecounter.

FIG. 21 schematically shows an alternate FBS Controller 1002 foraddressing through a clock signal, in accordance with certain exemplaryembodiments. In this example, the FBS Controller 1002 includes a counter2102 that operates substantially as the counter 2002, but furtherincludes a reset signal coming from a power-on-reset circuit and/or fromthe SPI. This resets the counter when the chip is powered on orarbitrarily when the controller 202 sends a reset signal through theSPI. This mechanism can be used to ensure that all chips in the arraybegin with the same FBS address (e.g. 1) at start up, and can be resetto the same value (e.g. 1) in the event that certain ASICs may have lostcount over time.

However the FBS interface is implemented, the phased array system 100and the beam forming ASICs 206 typically would be implemented such thatall beam forming ASICs 206 in the phased array system 100 share the sameFBS control lines/signals 1003 and therefore select the same registerset in the register banks across all beam forming ASICs at substantiallythe same time (e.g., by decoding the same address or by incrementingthrough the register sets of the register banks in lock-step with oneanother). Thus, for example, for a given register selection address, thecorresponding register sets across the phased array system 100 can bepopulated with data that points a beam in a particular direction, and,furthermore, the register sets corresponding to different registerselection addresses can be configured to point the beam in a differentdirection (and, in certain exemplary embodiments as discussed below,also to change the number of active beam forming channels and/or adjustthe DC power in one or more beam forming channels), thus changing suchthings as the effective aperture, G/T, EIRP, directivity, or DC powerconsumption of the phased array system 100. Given that the registerselection address can be updated quickly through the FBS controllines/signals 1003, the beam forming operation of the phased arraysystem 100 can be changed rapidly without having to program each beamforming channel 408 across all beam forming ASICs 206, thus allowing forrapid changes in effective aperture, G/T, EIRP, directivity, or DC powerconsumption of the array.

FIG. 11 is a block diagram schematically showing components of aregister bank 1006, in accordance with certain exemplary embodiments.Among other things, the register bank 1006 includes M register sets 1106and a switch 1102 that passes a selected one of the register sets 1106to the beam forming channel 408, based on a register selection signalfrom the FBS controller 1002. In certain embodiments, the register setsmay be accessed randomly (e.g., the beam forming controller 202 canaddress each register set individually and switch between them in anon-sequential manner, such as, for example, switching from register set1 to register set 5 to register set 3 and so on), while in otherembodiments, the register sets may be accessed sequentially or in around-robin fashion (e.g., the beam forming controller 202 may cause theswitch 1102 to step through the register sets in order from 1 to M andoptionally back to 1).

It should be noted that, typically, the register selection signals 1003from the beam forming controller 202 are provided to all of the beamforming ASICs 206 such that all beam forming channels 408 across allbeam forming ASICs 206 are switched to the addressed register set atsubstantially the same time, e.g., if the beam forming controller 202addresses register set 5, then all beam forming channels 408 across allbeam forming ASICs 206 are switched to the corresponding register set 5through a single addressing operation by the beam forming controller202.

A major advantage of such use of register banks over conventionaltechnology is that the beam forming ASICs 206 (and hence the phasedarray system 100) can switch between register sets at a much higher ratethan the beam forming controller 202 can re-program a full complement ofregister sets across all beam forming ASICs. Thus, switching betweendifferent beam forming operations (e.g., switching between a transmitmode and a receive mode, or making adjustments to a beam-formed signal,orientation of the beam, directivity, EIRP, G/T, or DC power) can beaccomplished at a much higher rate than in conventional systems. Suchfast beam switching is likely to become a critical element of manyfuture phased array systems such as for use in 5G applications and canenable different beam forming on each timing frame of a waveform.

Exemplary embodiments may be particularly useful for preprogramming andfast beam switching for a portion of the far field scan volume of thephased array system, up to and including the entire far field scanvolume of the phased array system.

FIG. 22 schematically shows a scan volume filled by N beams, inaccordance with certain exemplary embodiments. If there are sufficientnumber of register banks/sets to preprogram all N of the beams (e.g., Nregister sets per register bank), then fast beam switching can be usedto perform fast scans covering the entire far field scan volume usingonly the FBS control lines 1003, i.e., without having to reprogram anyof the register sets. In this case, the beam forming controller 202 maypreprogram all of the register sets in all of the register banks acrossall beam forming ASICs 206 with appropriate parameters for forming the Nbeams and then switch between register sets to selectively switchbetween beams. As discussed above, the beams may be accessed randomly(e.g., switching from beam 1 to beam N to beam 2, etc.) or may beaccessed sequentially (e.g., switch from beam 1 to beam 2 to beam 3 andso on).

Another advantage of such use of register banks is that, in certainexemplary embodiments, the beam forming controller 202 can write newvalues to a group of “inactive” register sets while beam formingoperations are being performed using a group of “active” register setsand in some embodiments even while the system is switching betweenregister sets that are not currently being written. Among other things,such selective reprogramming can be used to dynamically “frame” a beamforming target even as the target moves.

FIG. 23 schematically shows an example for selectively reprogrammingregister sets for dynamically framing a beam forming target, inaccordance with certain exemplary embodiments. This example is presentedusing a portion of the far field scan volume of the phased array systemcovered by 25 beams numbered 1-25. In this example, it is assumed thatthere is not a sufficient number of register banks/sets to preprogramthe entire far field scan volume. In FIG. 23(A), it is assumed that thetarget is within the area covered by beam 8, and therefore beam 8 wouldbe configured using one of the register sets of the register banks,which would be the “active” register set. If the target moves out of thearea covered by beam 8, then the target essentially must move into thearea covered by beam 2, beam 3, beam 4, beam 7, beam 9, beam 12, beam13, or beam 14 before moving into the area covered by other beams. Withthis knowledge, the beam forming controller 202 can preconfigure otherregister sets in the register banks with the parameters for beams 2, 3,4, 7, 9, 12, 13 and 14. The beam forming controller 202 then can trackmovement/position of the target to detect the target leaving the areacovered by beam 8 and entering the area covered by one of the otherpreprogrammed beams. The beam forming controller then can perform fastbeam switching to switch the phased array system to the appropriate beambased on the new position of the target and can reprogram some of theregister sets to “re-frame” the target based on the new beam.

For example, assume that the target moved from the area covered by beam8 into the area covered by beam 13, as depicted in FIG. 23(B). The beamforming controller 202 could switch from beam 8 to beam 13 and thenreconfigure the register sets that were formerly configured for beams2-4 to include the parameters for beams 17-19, thereby “re-framing” thetarget about beam 13. In this case, the register sets configured withparameters for beams 7-9 and 12-14 may not need to be reconfiguredbecause beams 7-9 and 12-14 are part of the new frame.

Now assume that the target moved from the area covered by beam 13 intothe area covered by beam 19, as depicted in FIG. 23(C). The beam formingcontroller 202 could switch from beam 13 to beam 19 and then reconfigurethe register sets that were formerly configured for beams 7, 8, 9, 12and 17 to include the parameters for beams 15, 20, 23, 24 and 25,thereby “re-framing” the target about beam 19. In this case, theregister sets configured with parameters for beams 13, 14, 18 and 19 maynot need to be reconfigured because beams 13, 14, 18 and 19 are part ofthe new frame.

It should be noted that, in certain embodiments, the example of FIG. 23could be implemented using nine register sets per register bank, giventhat parameters for nine beams are stored at any given time in thisexample. Thus, such framing can reduce the number of register sets perregister bank needed for a particular implementation, which in someembodiments could allow more beam forming channels to be supported byeach beam forming ASIC 206. FIG. 24 schematically shows exemplaryregister set configurations for the example of FIG. 23 , in accordancewith certain embodiments. Here, each register bank includes nineregister sets labeled for convenience as Register Sets A through I. Forthe framing scenario of FIG. 23(A), the beam forming controller 202 mayconfigure the register sets in all register banks across all beamforming ASICs 206 as follows: Register Set A configured with parametersfor beam 2; Register Set B configured with parameters for beam 3;Register Set C configured with parameters for beam 4; Register Set Dconfigured with parameters for beam 7; Register Set E configured withparameters for beam 8; Register Set F configured with parameters forbeam 9; Register Set G configured with parameters for beam 12; RegisterSet H configured with parameters for beam 13; and Register Set Iconfigured with parameters for beam 14. In this example, the beamforming controller 202 would activate Register Set E (i.e., to operatebeam 8) in all register banks across all beam forming ASICs 206.

For the re-framing scenario of FIG. 23(B), the beam forming controller202 may reconfigure the register sets in all register banks across allbeam forming ASICs 206 as follows: Register Set A reconfigured withparameters for beam 17; Register Set B reconfigured with parameters forbeam 18; and Register Set C reconfigured with parameters for beam 19.Thus, only three register sets per register bank would need to bereconfigured in this example. In this example, the beam formingcontroller 202 would activate Register Set H (i.e., to operate beam 13)in all register banks across all beam forming ASICs 206.

For the re-framing scenario of FIG. 23(C), the beam forming controller202 may reconfigure the register sets in all register banks across allbeam forming ASICs 206 as follows: Register Set A reconfigured withparameters for beam 15; Register Set D reconfigured with parameters forbeam 20; Register Set E reconfigured with parameters for beam 23;Register Set F reconfigured with parameters for beam 24; and RegisterSet G reconfigured with parameters for beam 25. Thus, only five registersets per register bank would need to be reconfigured in this example. Inthis example, the beam forming controller 202 would activate RegisterSet C (i.e., to operate beam 19) in all register banks across all beamforming ASICs 206.

Thus, the beam forming controller 202 may include circuitry configuredto preconfigure register sets to frame a particular target based on theposition of the target, track movement of the target to a new position,perform fast beam switching to select an appropriate beam configurationbased on the new position, and reconfigure a subset of the register setsto re-frame the target based on the new position.

In addition to the use of register banks, or separate from the use ofregister banks, certain embodiments include additional logic allowingthe beam forming controller 202 to selectively control DC powerconsumption of individual beam forming channels, e.g., for selectivelypowering on and off circuitry in the beam forming channels (e.g., whichcan be used to effectively shut off unneeded beam forming channels andhence to effectively control the number of “active” beam formingchannels) and in some embodiments also for adaptively adjusting power tocircuitry in the beam forming channels (e.g., which can be used toreduce power consumption by one or more active beam forming channels inappropriate situations). Conventionally, the circuitry in a beam formingchannel is powered on and consumes electric power even if, say, thegain/amplitude for the beam forming channel is programmed to zero. Manyapplications, such as in 5G communication devices, are very sensitive topower consumption, so the ability to selectively control DC power toindividual beam forming channels helps to reduce power consumption andtherefore provides a major advantage over conventional technology. Suchselective control of individual beam forming channels can be donethrough the register sets (e.g., deriving a power control parameter fromthe existing codeword information such as using the gain/amplitudeparameter as an on/off or power level indicator, designating one or morepreviously unused codeword bits as an enable/disable control or powerlevel control for the corresponding beam forming channel, or adding anew register to the register set to control the beam forming channel) orcan be done outside of the register sets (e.g., using a separateregister in the beam forming ASIC to selectively control each beamforming channel).

The ability to selectively turn on and off individual beam formingchannels also allows the system to selectively change the effectivedirectivity of the array. For example, for a far target, all beamforming channels might be turned on for maximum array directivity andrange, whereas for a near target, outer beam forming channels might beturned off to reduce array directivity and reduce DC power since maximumarray directivity and maximum range generally are not required.

FIG. 12 is a block diagram schematically showing components of a beamforming channel 408 including active power control in accordance withcertain embodiments. Here, the beam forming channel 408 includes, inaddition to amplitude and phase control circuitry 502, a decoder 1202and a power controller 1204. Based on power control parameters receivedfrom the register set 406 (e.g., one or more bits in the codeword), thedecoder 1202 produces a power control signal to the power controller1204 (e.g., an on/off signal, or a power level signal), which in turnselectively controls DC power to some or all of the amplitude and phasecontrol circuitry 502. In some embodiments the power controller 1204 mayinclude a power switch that is controlled by the output of the decoder1202 to turn on and off certain circuitry of the beam forming channel.In alternative embodiments, the power controller 1204 may include adigital potentiometer, digital to analog converter (DAC), or othercomponent to control voltage and/or current provided to certaincircuitry of the beam forming channel.

As discussed above, transmit path circuitry in a transmit-only ordual-mode beam forming channel 408 typically includes a power amplifier,while receive path circuitry in a receive-only or dual-mode beam formingchannel 408 typically includes a low noise amplifier. The beam formingchannel 408 also may include additional amplifiers and/or buffers. Giventhat such amplifiers and buffers typically consume a relatively largeamount of DC power when enabled, the active power control discussedherein typically would include the ability to turn off such componentsand/or the ability to reduce the amount of DC power provided to orotherwise consumed by such components.

Importantly, in certain situations, such active power control can beused to save DC power while maintaining the full effective aperture of abeam-formed signal such that DC power can be conserved without“widening” the beam (i.e., fewer active elements generally results in awider/fatter beam). For but one example, when the output powerrequirement reduces for a given beam forming channel, the DC current inthe power amplifier can be reduced in that beam forming channel. In thisway, all elements in the array can remain active, but overall DC powerconsumption can be reduced.

FIG. 13 schematically shows the contents of a beam forming controlcodeword for controlling a beam forming channel, in accordance withcertain embodiments. This codeword includes a power on/off field, a modeselection field (i.e., to switch between transmit mode and receive modefor use with dual-mode elements), phase parameters, and gain/amplitudeparameters. Using such a codeword, a particular beam forming channelconceivably can be switched between being enabled in transmit mode,enabled in receive mode, and disabled. When used in combination withregister banks, such switching can be pre-programmed and can beaccomplished at a high rate compared to conventional technologies whichswitch between modes more slowly and do not allow for disabling power toreduce power consumption.

FIG. 14 schematically shows the use of a separate power control registeras part of each register set 406, in accordance with certain exemplaryembodiments. Here, each register set includes power control registerthat is separate from the codeword register(s) used to conveygain/amplitude parameters, phase parameters, and optionally theoperational mode for the beam forming channel. One possible advantage ofusing a separate power control register in the register sets is that theactive power control circuitry may be implemented without modifying (orsubstantially modifying) the circuitry that uses the codewordregister(s), although, when used in combination with register banks, theswitching logic may need to be modified to include the power controlsignal.

FIG. 15 schematically shows the use of a separate power control registerseparate from the register sets 406, in accordance with certainembodiments. Here, a power control register, separate from the registersets 406, is used to control power for all of the beam forming channels408 of the beam forming ASIC 206. For example, the power controlregister may include Y bits, with each bit controlling power for aseparate one of the beam forming channels 408, although the powercontrol register may be encoded in other ways. One possible advantage ofusing a power control register separate from the register sets is thatthe active power control circuitry can be implemented without modifying(or substantially modifying) the circuitry that uses the register sets406, even when used in combination with register banks (since the activepower control circuitry can be implemented substantially outside of suchcircuitry).

The power control parameter for a beam forming channel 408 may bederived in other ways. For example, some embodiments may use thegain/amplitude parameter as an indicator of power control, e.g.,disabling or reducing power to certain circuitry if the gain/amplitudeis set to zero, or controlling DC power consumption of certain circuitrybased on the gain/amplitude parameter.

It should be noted that, while various exemplary embodiments aredescribed above with reference to phased array systems having aplurality of beam forming ASICs (e.g., as depicted in FIG. 2 ), it isconceivable for all beam forming channels and related circuitry of aphased array system to be implemented on a single beam forming ASIC orsubstrate and in some cases even for the entire phased array system tobe implemented on a single beam forming ASIC or substrate.

Thus, using fast beam switching and/or active power control mechanismsas described herein, phased array systems can support a wide range ofbeam forming operations.

For example, as shown in FIG. 25 , the phased array system maypreconfigure a plurality of register sets in each of a plurality ofregister banks (block 2502), select a register set for a beam formingoperation (block 2504), and send fast beam switching control signals toactivate the selected register set across the plurality of registerbanks for performing the beam forming operation (block 2506). Of course,the phased array system may recycle from block 2506 to block 2504 toselect a new register set and send fast beam switching control signalsto switch to the new register set, or the phased array system mayrecycle from block 2506 to block 2502 to reconfigure one or moreregister sets.

Additionally or alternatively, as shown in FIG. 26 , the phased arraysystem may preconfigure a plurality of register sets in each of aplurality of register banks with parameters for beams covering a full 2Dscan volume of a phased array system (block 2602), select a register setfor a beam forming operation (block 2604), and send fast beam switchingcontrol signals to activate the selected register set across theplurality of register banks (block 2606). Of course, the phased arraysystem may recycle from block 2606 to block 2604 to select a newregister set and send fast beam switching control signals to switch tothe new register set.

Additionally or alternatively, as shown in FIG. 27 , the phased arraysystem may preconfigure a plurality of register sets in each of aplurality of register banks with parameters for beams covering a targetarea and areas surrounding the target area (block 2702), send fast beamswitching control signals to activate the register set for the beamcovering the target area (block 2704), monitor movement of a target inthe target area (block 2706), detect movement of the target into a newtarget area from among the surrounding target areas (block 2708), sendfast beam switching control signals to activate the register set for thebeam covering the new target area (block 2710), and reconfigure at leastone register set in each of the plurality of register banks so that theregister banks contain parameters for beams covering the new target areaand areas surrounding the new target area (block 2712). Of course, thephased array system may recycle from block 2712 to block 2706 to monitormovement of the target in the new target area.

Additionally or alternatively, as shown in FIG. 28 , the phased arraysystem may determine parameters for a beam covering a target areaincluding a plurality of active beam forming channels and at least oneinactive beam forming channel (block 2802), preconfigure a register setin each of a plurality of register banks with the parameters for thebeam covering the target area (block 2804), and send fast beam switchingcontrol signals to activate the register set across the plurality ofregister banks (2806).

Of course, such phased array system may perform other beam formingoperations described herein involving fast beam switching and/or activepower control.

Although the above discussion discloses various exemplary embodiments ofthe invention, it should be apparent that those skilled in the art canmake various modifications that will achieve some of the advantages ofthe invention without departing from the true scope of the invention.

1-22. (canceled)
 23. A beam forming integrated circuit for use in aphased array system, the beam forming integrated circuit comprising: aplurality of beam forming channels, each beam forming channel includingbeam forming circuitry configured to process signals for a beam formingelement to produce a beam-formed signal; and for each beam formingchannel, at least one individually addressable and programmable registerset configured to store operating parameters for the beam formingchannel, wherein a selected register set associated with each beamforming channel is pre-programmed with operating parameters for changingdirectivity characteristics of the beam-formed signal; and fast beamswitching circuitry that receives fast beam switching control signalsfrom a fast beam switching control interface, the fast beam switchingcircuitry configured to simultaneously switch each beam forming channelto the pre-programmed operating parameters from the selected registerset associated with the beam forming channel based on the fast beamswitching signals from the fast beam switching control interface tochange the directivity characteristics of the beam-formed signal.
 24. Abeam forming integrated circuit according to claim 23, wherein the fastbeam switching circuitry is configured to allow for random access to theregister sets.
 25. A beam forming integrated circuit according to claim23, wherein the fast beam switching circuitry is configured to allow forsequential access to the register sets.
 26. A beam forming integratedcircuit according to claim 23, wherein the fast beam switching circuitryis configured to allow for round-robin access to the register sets. 27.A beam forming integrated circuit according to claim 23, furthercomprising a programming interface for programming the register banks.28. A beam forming integrated circuit according to claim 27, wherein thefast beam switching control interface is part of the programminginterface.
 29. A beam forming integrated circuit according to claim 27,wherein the fast beam switching control interface is separate from theprogramming interface.
 30. A beam forming integrated circuit accordingto claim 23, wherein the fast beam switching circuitry is configured toselect the register set based on a parallel address.
 31. A beam formingintegrated circuit according to claim 23, wherein the fast beamswitching circuitry is configured to select the register set based on aclock signal.
 32. A beam forming integrated circuit according to claim23, wherein the operating parameters include an amplitude parameter anda phase parameter.
 33. A beam forming integrated circuit according toclaim 23, wherein at least one of the beam forming channels is adual-mode beam forming channel including transmit path circuitry foroperating in a transmit mode, receive path circuitry for operating in areceive mode, and mode selection circuitry for switching between thetransmit mode and the receive mode based on a mode selection parameterin the operating parameters for the beam forming channel.
 34. A beamforming integrated circuit according to claim 23, wherein at least onebeam forming channel includes active power control circuitry configuredto selectively control DC power consumption of the beam forming channelbased on a power control parameter for the beam forming channel for atleast one of (1) reducing DC power consumption of the phased arraysystem or (2) selectively changing the effective directivity of thephased array system.
 35. A beam forming integrated circuit according toclaim 34, wherein the power control parameter for the beam formingchannel is derived from the operating parameters provided to the beamforming channel.
 36. A beam forming integrated circuit according toclaim 34, wherein the power control parameter for the beam formingchannel is derived from a register separate from the register bank. 37.A beam forming integrated circuit according to claim 34, wherein theactive power control circuitry is configured to selectively turn on oroff at least some beam forming circuitry of the beam forming channel.38. A beam forming integrated circuit according to claim 34, wherein theactive power control circuitry is configured to selectively adjust apower level of at least some beam forming circuitry of the beam formingchannel.
 39. A phased array system for controlling the directivity of abeam-formed signal, the system comprising: a plurality of beam formingelements; a plurality of beam forming integrated circuits according toclaim 23; and a beam forming controller configured to pre-program theselected register set associated with each beam forming channel with theoperating parameters for changing the directivity characteristics of thebeam-formed signals of the plurality of beam forming integrated circuitsand to produce the fast beam switching control signals to causesimultaneously switching of the plurality of beam forming channels ofthe plurality of beam forming integrated circuits to the pre-programmedoperating parameters from the selected register set of the correspondingregister bank to change the directivity characteristics of thebeam-formed signals of the plurality of beam forming integratedcircuits.
 40. A phased array system according to claim 39, wherein thebeam forming controller is configured to selectively turn on or off oneor more individual beam forming channels to selectively control DC powerconsumption of the phased array system as part of changing thedirectivity characteristics of the beam-formed signal.
 41. A phasedarray system according to claim 39, wherein each beam forming channel isassociated with a plurality of individually addressable and programmableregister sets enabling pre-programming of different beam-formed signalcharacteristics.
 42. A method for controlling the directivity of abeam-formed signal in a phased array system having a plurality of beamforming elements, a plurality of beam forming integrated circuitsaccording to claim 23, and a beam forming controller, the methodcomprising: pre-programming, by the beam forming controller, theselected register set associated with each beam forming channel with theoperating parameters for changing the directivity characteristics of thebeam-formed signals of the plurality of beam forming integratedcircuits; and producing, by the beam forming controller, the fast beamswitching control signals to cause simultaneously switching of theplurality of beam forming channels of the plurality of beam formingintegrated circuits to the pre-programmed operating parameters from theselected register set of the corresponding register bank to change thedirectivity characteristics of the beam-formed signals of the pluralityof beam forming integrated circuits.